Mayer was the first female engineer at Google, hired in 1999 and has run the company’s consumer operations including Google Maps and Zagat for the past two years. She plays a key role in what consumers see when they go to Google, including that new “Doodle” program that redesigns the corporate name regularly.

Mayer also appears frequently in the media, often speaking about Google initiatives as well as broader topics like women in Silicon Valley. That’s a change from Scott Thompson, the short-lived Yahoo experiment, and Ross Levinsohn, who has served as interim CEO, yet didn’t merit a single mention in today’s release announcing Mayer’s appointment.

Here’s some quick biographical background on her:

Degrees – Mayer received her B.S. in symbolic systems and her M.S. in computer science from Stanford University. (We’ll assume Yahoo double checked that info this time.) For both degrees, she specialized in artificial intelligence.

How she describes herself –In a 2011 interview with WSJ — “[W]hat’s really important is if you’re a geek. People ask me a lot what it’s like to be a woman at Google. I don’t think of my experience that way. I’m a geek at Google.”

Corporate fighting stripes earned 1 – Versus Microsoft’s Bing — As head of Google’s search, Mayer engaged in all out fight with Microsoft’s Bing when it launched. As this month’s Microsoft write down signaled, she won.

Corporate fighting stripes earned 2 – Versus Groupon — After Groupon rejected Google’s $6 billion offer, Mayer went on the offensive, plotting Google’s competitor to Groupon. “We’re looking at how can we take this technology and put it to use, especially in the location space,” she told MediaBistro.

She has high spirits even when she falls –From a 2006 story about a skiing tournament during Davos — This year, more non-Germans were invited, including Marissa Mayer, an American vice president of Google Inc. Handed the last start number, Ms. Mayer faced a rutted ski course by the time her turn came. “I just hope I don’t fall,” she said while waiting at the back of the starting line. Her run ended with a spectacular tumble a mere three gates from the finishing line. “I guess I psyched myself out,” she said afterward. The organizers awarded Ms. Mayer a special prize for showing “the best spirit.”

More glass half full – Her “favorite mistake” as told to Newsweek last year — “It was my job to oversee everything that had to do with Google search: what users saw on the homepage, and all the code written behind it, right down to the very last character. But we accidentally introduced a stray “/”—a slash—on our servers. It was the slash heard round the world. Suddenly, every page on the Internet was popping up with a big red warning: THIS SITE MAY HARM YOUR COMPUTER. You couldn’t access anything on Google. It was as if the Internet was broken.”